A Chinese woman wears a mask to protect from particles blown in during a sandstorm as she walks in the street on May 4, 2017 in Beijing, China. Sandstorms are common in northern China during the spring season and are caused when heavy winds from Mongolia in the north brings sand and pollutants that can blanket Chinese cities and cause air quality to deteriorate. (Photo by Kevin Frayer/Getty Images)

Chinese soldiers leave after Chinese President Xi Jinping inspected troops of People's Liberation Army (PLA) Hong Kong Garrison at the Shek Kong Barracks in Hong Kong, Friday, June 30, 2017. Xi landed in Hong Kong Thursday to mark the 20th anniversary of Beijing taking control of the former British colony, accompanied by a formidable layer of security as authorities showed little patience for pro-democracy protests. (Photo by Kin Cheung/AP Photo)

A Chinese exhibitor checks lighting products at a booth during the China Import and Export Fair, also known as Canton Fair, in the southern Chinese city of Guangzhou October 15, 2015. Around two thirds of exporters at China's largest trade fair expect the slowdown in their markets to persist for at least six months, a Reuters poll has found, with the country expected to announce its slowest economic growth in decades early next week. (Photo by Bobby Yip/Reuters)

This April 9, 2016 photo provided by Bertrand Piccard via Global Newsroom shows Piccard taking a selfie on board Solar Impulse 2 during a test flight over the Pacific Ocean. The solar-powered airplane on an around-the-world journey had traveled 80 percent of the way from Hawaii to California by Saturday, April 23. The aircraft's destination on this leg of the journey is Mountain View, Calif., at the southern end of San Francisco Bay. (Photo by Bertrand Piccard/Global Newsroom via AP Photo)

In this June 29, 2016 file photo, boats docked at Central Marine in Stuart, Fla., are surrounded by blue green algae. The 153-mile-long Indian River Lagoon has been plagued by harmful algae blooms. Water quality testing data analyzed by the AP showed the average phosphorous level – a byproduct of fertilizers and human waste that algae thrive on, rose nearly 75 percent between 2000 and 2016. (Photo by Greg Lovett/The Palm Beach Post via AP Photo)

An anti-Gaddafi fighter tests an anti-aircraft gun southwest of Sirte, Libya one of Muammar Gaddafi's last remaining strongholds, September 16, 2011. A timeline of images dating from 2010 from Sirte, Libya, the home town of deposed Libyan leader Muammar Gaddafi. Libyan forces battling Islamic State in the city of Sirte say they have defeated the militant group after months of street to street fighting backed by U.S. air strikes. Islamic State took control of the city more than a year ago and set up its main base outside Syria and Iraq. (Photo by Goran Tomasevic/Reuters)

A dog at the Zoozashchita-NN veterinary clinic in Nizhny Novgorod, Russia on February 19, 2021. On February 13, 13 stray dogs with bright blue fur were found and caught at the Dzerzhinskoye Steklo (Dzerzhinsk Glass) factory producing acrylic glass and prussic acid in the city of Dzerzhinsk. The dogs' fur tested positive for the Prussian blue pigment; now the dogs are under supervision at the Zoozashchita-NN vet clinic in Nizhny Novgorod. (Photo by Mikhail Solunin/TASS)

Festival-goers enjoy a fairground ride at Reading Festival in Reading, west of London, on August 27, 2021. As coronavirus covid-19 infection levels rise across the country, vaccines will be offered to revellers throughout the weekend. The organiser of Reading and Leeds Festivals has said such events are arguably “safer places to be” because attendees have been tested for covid-19. The festivals are returning this year with headliners including Stormzy, after being cancelled last year due to the pandemic. (Photo by Daniel Leal-Olivas/AFP Photo)